There are many reasons why Freaks and Geeks is such an amazing series--the all-star cast (including the mother, played by Becky Anne Baker, who now plays Hannah Horvath's mother in Girls), the production quality, the writing. But what really did it for me was the soundtrack. Most of the major moments throughout the series are enhanced by music from the 70s and 80s. From Sam's "slow dance" to Styx's "Come Sail Away" in the pilot episode, to Jason Segel's silky, sexy disco dance in the final episode, and everything in between.
My absolute favorite scenes--and quite possibly some of the greatest musical moments in television history--are when Nick sings "Lady L" (which was written by Jason Segel), and when Lindsey's parents debate the sexual implications of The Who's "Squeezebox."
Great music. Great entertainment. It was a crime against television to cancel this show.